Process for producing lubricating oil



' Feb. 20, 1934.

u. B. BRAY r AL PROCESS FOR PRODUCING LUBRIGATING OIL Filed Feb. 23, 1952 INVENTORS NM MW L 1 w 8 Q 8 .v

Ulric B.Bray 5 C/aacze 55m?! BY 6 I ATTORNEY.

IV mN kmsgmw vAwN A AI 1 I mm RN \wQ kmvbng Patented Feb. 20, 1934 UNITED STA Ulric B. Bray,

Glendale, Calif., .assignors to Los Angeles, Calif., a corpany of California, notation of California Los Angeles, and Claude E. Swift,

Union Oil om- Applicatio'n February 23, 1932. Serial No. 594,604

Claims.

This invention relates to a process for theproduction of lubricating oil. More particularly it relates to a process for the production of lubricating oils by the use of aluminum chloride. Superior lubricating oils are characterized by having a low temperature viscosity susceptibility, i. e., minimum change in viscosity with a change in temperature, a low Conradson carbon value, a low Sligh oxidation value, a high color stability towards sunlight and a high resistance to oxidation. I a

By the present methods of producing lubricating oil it is practically impossible to produce an oil possessing all of theforegoing desired charac teristics. Overhead distillates from asphaltic oil which have been treated to produce lubricants are usually characterized by a high temperature viscosity susceptibility, a low Conradson carbon value, a high Sligh oxidation value, a low color stability towards sunlight and a low resistance to oxidation. Lubricating oil 'produced from paraffin base crude and which has not been distilled overhead usually is characterizedby having a low temperature viscosity susceptibility, a moderate- 1y high Sligh oxidation value, a high Conradson value, a high color stability to the action of 'light and a high resistance towards oxidation.

In the prior application of Ulric B. Bray, Serial No. 466,189, dated July 7, 1930, and application Serial No. 594,606, dated Feb. 23rd, 1932, processes are shown in which lubricating oils can be produced from asphaltic oil which have a low temperature viscosity susceptibility, a. low Conradson and a low Sligh oxidation value. In these processes of Ulric B. Bray, it has been shown that asphaltic oil usually contains a mixture of oils some of which exhibit a high temperature viscosity susceptibility and some of which exhibit a low temperature viscosity susceptibility. Furthermore-it has been shown that these heavy oils present in the crude oil, which exhibit to a marked. degree a low temperature viscosity susceptibility,

cannot be distilled overhead without a substantial increase of their temperature viscosity susceptibility. This is especially true where asphalt is present in the oil and which seems to catalytically cause the heavy oils present, upon distillation, to become more susceptible to a change in viscosity with a change in temperature. In conserving the low temperature viscosity susceptibility of these heavy oils it has been shown that it is necessary to prevent the exposure of the oil to excessive temperatures for prolonged periods. Temperatures above 650 F. are highly detrimental to the temperature viscosity susceptibility of the oil and are, therefore,

res PATENT onuce avoided. Furthermore, the

distillation of the light fractions from the asphalt and lubricating fractions is discontinued at the point at which upon further vaporization of the oils present in having a viscosity Saybolt Universal at 100 the residue oils'would b in excess of 400500 seconds e vaporized 'After having distilled off the light fractions from the crude oil under conditions which do not ead gasolin viscosity susceptibility of resent in the residue the asphalt by the use 01, mixtures of ether volatile hydrocarbon e and light naphthas. By the term asphalt is meant constituentsof the crude oil precip itated by but undissolved by the foregoing solvents. However, the preferable solvent employed is one which is obtained during the rectification of'natural gasoline and which is normally in the vapor state at atmospheric drocarbons pressure and temperature. include methane, ethane, propane, iso- Such hybutane and butane and mixtures thereof. During the rectification of casinghead gasoline by the so called drocarbons are obtaine stabilizing method" the foregoing hyd as overhead products.

They are liquefied by cooling and compression in the conventional manner and are drawn off into pressure chamb ers where they are maintained in a liquid state until used. A typical solvent emthe following composition: 6.72%

19.91% isobutane and loying for the separation of the asphalt Such a solvent is valuable separation of the aslatter is still charachigh Conradson carbon value. tion by Ulric B. Bray, Ser. No. 3rd, 1932, the inventor has a solvent consisting the balance mainly propane esidues into asphalt and ill have a low Conradell as -a low. temperature viscosity susceptibility. However, there are certain undesirable unsaturated hydrocarbons present in the finished oil which exhibit a poor color stability towards the action of sunlight and which are susceptible to oxidation. We have discovered that been produced from, asphaltic the inherent characterditions which conserve these oils which have residues under conistics of the oil and which exhibit a low temperature viscosity susceptibility,

a low Conradson carat a temperature sufliciently high to crack the unstable constituents present in the oil which influence the color stability of the oil and the oxidation value but below which there is any impairment of the temperature viscosity susceptibility of the oil. Certain of these unstable hydrocarbons present are converted into hydrocarbons of .lower molecular weight and are removed as vapors from the oil, whereas others are polymerized and removed from v the oil as tars.

The extracted and acid aluminum chloride treated oil produced by our process possesses most of the valuable characteristics which are common to superior lubricants.

'Sometimeswe find it necessaryto acid and alkali treat the aluminum chloride treated oil to remove'therefrom small quantities of impurities in theform of tar or aluminum chloride.

It is, therefore, an object of our invention to produce lubricating oils having superior qualities from oils containing asphalt, by removing the asphalt from the oil with solvents under conditions which will not impair the inherent characteristics of the oil and then to remove the unstable hydrocarbons from the oil with aluminum chloride.

It is another object of our invention to distill asphaltic oil to a temperature below which no substantial impairment in the temperature viscosity susceptibility of the residual oil occurs, to separate the asphalt from the oil and then treat the oil with anhydrous aluminum chloride to remove therefrom oils which are unstable in. character.

Figure 1 is one form of apparatus in which we maycarry out our process.

Referring more particularly to Figure 1, crude oil in tank 1 passes through valve 2 to pump 3 which forces it through line 4 to pipe still 5 where the temperature of the oil is raised to a temperature not exceeding 650? F. The heated oil passes from pipe still 5 through line 6 into fractionation column 7 where the light fractions are removed and pass out as vapors from the column 7 through condenser 9 where they are liquefied and pass into gas and water separator 10 where the non-con densable gases and water are removed. The light oil fractions in separator 10 then pass by means of valve 11 and line 12 to light hydrocarbon storage tank 13.

The asphaltic 'oil bottoms in column 7 are removed through valve 17 to pump 18 which forces it through line 19 into cooler 20 where the temperature of the oil is lowered to about 90 F.-110 F. The cooled oil passes from cooler 20 through line 19 into agitator 26 where it is mixed with light solvent coming from tank 22 through valve 23, line 24, pump 25 and line 24. This solvent may be composed chiefly of propane with minor amounts of methane, ethane, isobutane and normal butane, or it may be composed largely of ethane and propane with minor amounts of methane, isobutane and normal butane. We prefer to use a solvent having the following composition: 60% ethane, 34% propane, 4% isobutane, 2% butane. By using a solvent having the foregoing composition we are able to extract an oil from the asphaltic oil residue which is characterized by having a lowConradson carbon value and a low temperature viscosity susceptibility.

The mixture of residual oil and light hydrocarbon solvent in agitator 26 passes by means of line 27' into separator 28 where the undissolved asphalt settles out and is removed through valve 30 to pump 31 which forces it through line 32 to heater 33 where the temperature of the mass is raised sufficiently high to vaporize the solvent present in the asphalt. The heated mass passes from heater 33 through line 34 to separator 35 where the vapors separate from the asphalt and .are removed through line 39 to condenser 40 where any water present in the. vapors is condensed. The mixture of light hydrocarbon va- 36 and line 37 into asphalt storage tank 38.

The solvent solution of oilin separator 28 is removed through line29 to pump 47 which forces it through 29' into evaporator 48 where by aid of steam introduced through closed coil 52 the light solvent present is vaporized and passes out of evaporator 48 through line 50 into compressor 51-,

Where the vapors are compressed and forced through 50 to condenser 97 where they are liquefied and pass by means of line 46 to solvent storage tank 22.

The solvent free oil in evaporator 48 is removed through valve 53 to pump 54 which forces it through line 91 into treater 55 where itis mixed with anhydrous aluminum chloride introduced through port 56. The oil and aluminum chloride are agitated by means of blades 59 attached to shaft 92 which is rotated by means of pulley 58. Suflicient heat is applied to the aluminum chloride treater by means of burner 99 to maintain a temperature between'600 and 650% F. Any tar formed during the treatment settles out and is withdrawn at intervals through pipe 63 and valve 64 by stopping the agitation and allowing it to settle out. The light vapors formed in the treater are removed through line 60, liquefied by condenser 61 and pass by means of line 62 to a storage tank, not shown.

Condenser 57 surrounding outlet pipe 60 serves to cool the light vapors passing out of the treater 55 to a point below which there is any substantial loss of aluminum chloride vapors. A temperature of 350 F. in the exit vapors of the treating chamber 55 is normally sufliciently low to prevent any substantial loss of aluminum'chloride into the condensing system 61.

After the oil in treater 55 has been heated for a period sufficiently long to remove the unstable hydrocarbons present it is withdrawn through valve 65 into pump 66 which forces it through line 93 to cooler 67 where the temperature of the oil is lowered to about 80-l10 F. The cooled oil passes from cooler 67 through line 68 to agitator 72 where it is mixed with acid introduced from ,tank 69 through valve 70, pump 71 and line 94.

The mixture of oil and acid flow from agitator 72 to separator 74 where the sludge present in-the oil is allowed to settle out and is removed through valve 75 and line 76. Thesludge free oil in separator 74 passes into tank 78 where it is washed with alkali introduced from, tank 79 through valve 80, pump 81 and line 82. The alkalized oil is then washed free from caustic by water introduced from tank 83 throughvalve 84, pump 85 and line 82 into the oil in tank 78. The excess solved asphalt, separating alkali and wash water are removed from tank '78 through valve and line 96. v

The treated oil is removed from tank '78 through valve 86 and line 8'7 into storage tank 88. II desired the light oil present in the oil in tank 88 produced by the conversion of the high boiling point unstable hydrocarbons into low boiling point hydrocarbons may be distilled out in the conventional manner, not shown, in order to produce a finished oil having. the desired viscosity and flash point.

As an example of the method of carrying out our process, a California asphaltic crude oil in tank 1 is heated to a temperature not exceeding 650 F. in pipe still 5 and then sent to fractionating tower 7 where the light fractions are removed. The oil residue in column '7 is then cooled to a temperature of about 90110 F. in cooler 20 and then mixed with the light solvent from tank 22 in the proportion ofone part of asphaltic oil to three parts of solvent. The solvent solution of oil is separated from the undissolved asphalt and passes into evaporator 48 where the solvent is removed from the oil. The solvent free oil passes from evaporator 48 into treater 55 where it is mixed with about 10 pounds of anhydrous aluminum chloride per barrel of oil, then the oil and aluminum chloride is heated to 650 F. where it is maintained at this temperature with constant agitation for a period of from one to three hours. Agitation of the mass is then stopped and the tar bodies are permitted to settle out and are removed through line 63 and valve 64. The treated oil is then removed from treater 55 and cooled to a temperature of about 80 F.- F., after which it is treated with about 5 to 10 pounds of 98% H2804 per barrel of oil. The acid treated oil is then caustic and water washed until a neutral product is obtained-and then sent to storage tank 88. II desired, the light fractions present in the finished oil may be removed to improve the flash point and to increase the viscosity of the final product. This product so produced is a lubricating oil of superior quality.

It is to be understood that the foregoing example is merely illustrative of one form of carrying out our process and is not to be construed as limiting the invention which we claim.

We claim:

1. A process for the production of lubricating oil from oil containing asphalt which comprises commingling said oil with a solvent capableof dissolving the oil but substantially no asphalt, separating the solvent and oil from the undisthe solvent from the oil. contacting the substantially asphalt free oil with aluminum chloride at a temperature sufficiently high to convert the unstable hydrocarbons into reaction products and removing the aluminum chloride and reaction products from the treated oil.

2. A process as in claim 1 in which the treated oil is treated with acid.

3. A process as in claim 1 in which the treated oil is treated with acid and alkali.

4. A process for the production of lubricating oil from oil containing asphalt which comprises. commingling said oil with a liquefied normally gaseous hydrocarbon solvent to dissolve the oil and precipitate the asphalt, separating the oil dissolved in said solvent from the precipitated asphalt, removing the solvent from the substantially asphalt tree oil, contacting the substantially asphalt free oil with aluminum chloride at a temperature sufficiently high to convert the unstable hydrocarbons into reaction products and removing the aluminum chloride and reaction products from the treated oil.

5. A process as in claim 4 in which the solvent employed is a liquefied normally gaseous hydrocarbon containing a major portion of propane.

6. A process for the production of lubricating oil from an oil containing asphalt which comprises commingling said oil with liquid propane to dissolve the oil and precipitate the asphalt, removing the precipitated asphalt from the propane solution of oil, separating the propane from the substantially asphalt tree oil, commingling the substantially asphalt tree oil with aluminum chloride at a temperature sufficiently high to convert the unstable hydrocarbons into reaction products and removing the aluminum chloride and reaction products from the treated oil.

'7. A process as in claim 6 in'which the treated oil is treated with acid.

8. A process as in claim 6 in which the treated oil is treated with acid and alkali.

9. A process for the production of lubricating oil from oil containing asphalt which comprises distilling said oil to a point at which upon furthe:- distillation oil fractions will be vaporized having a viscosity of 500 seconds Saybolt Universal at 100 F., extracting said oil with a solvent capable of dissolving the oil but not the asphalt separating the oil dissolved in said solvent from the asphalt, separating the substantially asphalt free oil from the solvent, heating the substantially asphalt tree oil in the presence of aluminum chloride to a temperature sufliciently high to convert the unstable hydrocarbons into lower boiling point fractions, separating the lower boiling point fractions from the treated oil and subsequently separating the aluminum chloride and reaction products from the treated oil.

10. A process for the production of lubricating oil from oil containing asphalt which comprises distilling said oil to a temperature not exceeding 650 F., commingling the asphaltic oil residue in a solvent composed mainly of liquid ethane and liquid propane to separate asphalt, separating the solvent solution of oil from the undissolved asphalt, removing the solvent from the substantially asphalt free oil, treating the substantially asphalt free oil in the presence of aluminum chloride to a temperature not exceeding 650 F., and subsequently separating the aluminum chloride and reaction products from the oil.

ULRIC B. BRAY. CLAUDE E. SWIFT. 

